Extendable support structures

ABSTRACT

Various types of extendable support structures provide a lateral dimension that is defined by at least one lazy tong, and the longitudinal dimension is variable by extension and retraction of the at least one lazy tong. The extendable structure may include a plurality of adjacent and attached lazy tongs that are capable of supporting a significant load through the interconnection of the adjacent lazy tongs forming the structure. The extendable structure may be fully retracted to minimize the longitudinal dimension and thereby provide a compact structure, such as one that can be easily transported or stored. The extendable structure may be extended to a length as required for a particular purpose and limited to a maximum longitudinal dimension when the structure is being used to support a load. As such the various types of extendable support structures may be used in many scenarios, such as for providing a loading ramp, bridge, walkway, or working surface.

TECHNICAL FIELD

The present invention relates to support structures. More specifically,the present invention relates to support structures that can be extendedand retracted.

BACKGROUND

Support structures are used to sustain a load either continuously orover repeated intervals. For example, a floor structure may be used tocontinuously sustain a load provided by the gravitational force ofstatic objects placed on the floor structure. Bridges are used tosustain a load over repeated intervals, such as when objects repeatedlytravel across the bridge. Loading ramps are used to sustain a load asobjects pass up or down the loading ramp. Likewise, walls may sustain aload parallel to the ground such as heavy winds or moving objectscontacting the walls.

In certain situations, support structures such as these discussed abovemay indefinitely remain in a static condition. However, otherapplications for a support structure may require that it be extendableand retractable for various reasons. As one example, it may be arequirement that a support structure be portable, and to enhance theportability of the structure it may be desirable to reduce thelengthiest dimension of the structure by retracting it when it must betransported. Then, when the structure is positioned where it mustsupport a load, the structure is extended so that the load can be placedon the structure.

Providing a support structure that can be retracted and extended asnecessary requires that the support structure not be a rigid unitarystructure. Instead, the support structure must provide retractabilityand extendibility by incorporating flexibility into the design. However,the support structure must also be able to sustain the particular loadthat will be applied to the structure. Thus, such a support structuremust address at least these two contradictory constraints.

SUMMARY

Embodiments of the present invention address these and other problems byproviding a structure that is expandable from a retracted position sothat a longitudinal dimension of the extendable support structure isvariable. The extendable support structure may be retracted and expandedas necessary while providing support for a load when in an expandedstate that may range up to a maximum longitudinal dimension.

One embodiment of the present invention is an extendable supportstructure that includes adjacent lazy tongs that provide a lateraldimension to the support structure. The adjacent lazy tongs extend toprovide the variable longitudinal dimension and the adjacent lazy tongsare fixed together laterally at at least one point.

Another embodiment of the present invention is an extendable supportstructure that includes at least one lazy tong that provides the lateraldimension and has non-linear members, and the at least one lazy tongextends to provide a variable longitudinal dimension. The at least onelazy tong has a curvature present on at least one end of each non-linearmember. The curvature limits the longitudinal dimension by abuttinganother member when the at least one lazy tong is extended to maximizethe longitudinal dimension.

Another embodiment of the present invention is an extendable supportstructure that includes at least one lazy tong that provides the lateraldimension and has non-linear members. The at least one lazy tong extendsto provide a variable longitudinal dimension. At least one end portionwith a catch is connected to and is angled in relation to a centralportion for each non-linear member. Each central portion has a notch inat least one side, and the notch accepts a catch from another non-linearmember of the at least one lazy tong when the at least one lazy tongs isextended to maximize the longitudinal dimension.

Another embodiment of the present invention is an extendable supportstructure that includes at least one lazy tong that provides a lateraldimension. The at least one lazy tong extends to provide a variablelongitudinal dimension, and the at least one lazy tong forms an arc overat least a portion of the longitudinal dimension when extended.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of the present invention.

FIG. 2 is a plane view of the embodiment of FIG. 1.

FIG. 3 is a diagram illustrating a truss-like configuration for thedistribution of a load applied to the embodiment of FIG. 1.

FIG. 4 is a perspective view of a second embodiment of the presentinvention.

FIG. 5 is a plane view of the embodiment of FIG. 4.

FIG. 6 is a diagram illustrating the truss-like configuration andcompression loading for the distribution of a load applied to theembodiment of FIG. 4.

FIG. 7 is a perspective view of a third embodiment of the presentinvention.

FIG. 8 is a plane view of the embodiment of FIG. 7.

FIG. 9 is a diagram illustrating the truss-like configuration and thecompression and tension loading for the distribution of a load appliedto the embodiment of FIG. 7.

FIG. 10 is a perspective view of the embodiment of FIG. 7 in a fullyretracted position.

FIG. 11 is a partially exploded perspective view illustrating typicalassembly of the embodiment of FIG. 7.

FIG. 12 is a perspective view of members of one embodiment of thepresent invention that utilize integral pin attachments.

FIG. 13 is a perspective view of two extendable support structureembodiments, where one structure is fully retracted and the other isfully extended.

FIG. 14 is a perspective view of a vehicle that has an embodiment of theextendable support structure attached to a tailgate in a retractedstate.

FIG. 15 is a perspective view of the vehicle of FIG. 14 that has theextendable support structure pivoted away from the open tailgate whilein the retracted state.

FIG. 16 is a perspective view of the vehicle of FIGS. 14 and 15 that hasthe extendable support structure pivoted away from the open tailgatewhile in an extended state to form a loading ramp.

FIG. 17 is a perspective view of the vehicle of FIGS. 14-16 that has theextendable support structure pivoted away from the open tailgate whilein an extended position with legs attached to the structure to form atable.

FIG. 18 is a perspective view of an extendable support structureembodiment in its extended state that may be used for various purposesand that includes rails and members having multiple sizes.

FIG. 19 is a perspective view of the extendable support structure ofFIG. 18 in its retracted state.

FIG. 20 is a perspective view of an expandable room having fourextendable walls that are in their extended state and include anembodiment of an extendable support structure.

FIG. 21 is a perspective view of the expandable room of FIG. 20 wherethe four extendable walls are in their retracted state.

FIG. 22 is a perspective view of an embodiment of an extendable supportstructure in an extended state that includes adjacent lazy tongs thatare offset to permit the extendable support structure to have variousstructural forms.

FIG. 23 is a perspective view of the embodiment of FIG. 22 in aretracted state.

FIG. 24 is a perspective view of an embodiment of an extendable supportstructure in its extended state that forms an arc.

FIG. 25 is an perspective view of the embodiment of FIG. 24 in aretracted state.

FIG. 26 is a plane view of a portion of the embodiment of FIG. 24 thatillustrates the center hole relationship for the members.

FIG. 27 is a perspective view of a vehicle that has an embodiment of theextendable support structure attached to a truck bed as a cover in anextended state.

DETAILED DESCRIPTION

Embodiments of the present invention provide adjacent lazy tongs ofvarious configurations that form an extendable support structure. Theadjacent lazy tongs allow the structure to extend and retract as desiredby the user while sustaining loads applied to the surface of theadjacent lazy tongs. Therefore, the extendable support structure isbeneficial in that it is not permanently fixed in its extended state andcan be retracted for various reasons such as to store or transport thesupport structure.

The lazy tongs that are included in embodiments of the extendablesupport structure are jointed extensible frameworks. Traditionally, lazytongs have one end adapted to grasp an object and another end used by anoperator to trigger the extension or retraction of the lazy tongs. Thus,the user can extend the lazy tongs to grasp an object at a distance fromthe user to bring the object closer. As used herein, the term lazy tongsrefers to the jointed extensible framework and does not require that thejointed extensible framework include an end used for grasping or an endused as a handle for triggering extension or retraction.

Where adjacent lazy tongs are included in the embodiments of the presentinvention, they are positioned adjacently to provide the lateraldimension of the support structure. In the embodiments where multiplelazy tongs are used, they are adjacent and are interconnected in variousways discussed herein to fix the structure's lateral dimension and tocoordinate the extension of the adjacent lazy tongs to vary thelongitudinal dimension of the support structure. The at least one lazytong of the embodiments directly supports loads that are applied to thesupport structure where the loads create a force component that isperpendicular to both the lateral and longitudinal dimension of thesupport structure.

One embodiment of the extendable support structure 100 is shown in FIGS.1 and 2. The extendable support structure 100 includes adjacent lazytongs 102 and 104 that are formed by a series of members 106 that arejointed together, where each lazy tong 102, 104 is defined by two memberwidths. Lazy tong 102 includes members 106 forming a row 118 defined byone member width that are pivotally connected to members 106 that form arow 116 also defined by one member width. The adjacent lazy tong 104 isformed of members 106 forming a row 120 defined by one member width thatare pivotally connected to members 106 that form the row 116. Thus, therow 116 forms a portion of both the two adjacent lazy tongs 102 and 104.

Two lazy tongs 102, 104 are shown in FIG. 1 for illustrative purposesonly, and one skilled in the art will recognize that many rows ofmembers may be included in a repeating pattern to form several adjacentlazy tongs. The lateral dimension 124 of the extendable supportstructure 100 is defined by the number of members 106 that are adjacentin the lateral direction, where the number of members 106 define thetotal number of lazy tongs that are present. As is well known, lazytongs are extensible, and therefore, the extendable support structure100 has a longitudinal dimension 122 that is variable depending uponwhether the structure 100 is fully retracted or extended to some degree.As shown, the structure 100 is partially extended to provide atruss-like configuration discussed in more detail with reference to FIG.3.

Each member 106 has a first end 108, a central portion 110, and a secondend 112. The support structure embodiment 100 provides linear members106. As discussed below, the members 106 may have non-linear shapes aswell. The members 106 of this embodiment 100 have holes 115 that allowpins 114 to pass through in the lateral dimension 124. The pins 114 passthrough the holes 115 of the members 106 for each row 116, 118, and 120.Therefore, the adjacent lazy tongs 102 and 104 are fixed together atseveral points by the pins 114, and the adjacent lazy tongs 102, 104cooperate to extend and retract together as a unit.

One skilled in the art will recognize that the adjacent lazy tongs ofpresent in embodiments discussed herein may be attached at fewer thanevery point shown in FIGS. 1 and 2, such as by using pins that do notextend through every member 106 across the lateral dimension 124. Forexample, if an embodiment has four member widths to the lateraldimension 124 instead of three member widths as shown in FIG. 1, certainpins 114 may extend through the first two member widths and other pinsmay extend through the third and fourth member widths. At least one pin114 extends between the second and third member widths to establish atleast one fixed point between the lazy tong formed by the first twomember widths and lazy tong formed by the last two member widths.

FIG. 3 shows a diagram 300 of the distribution of force relative to thetruss-like configuration 304 of the embodiment 100 when partiallyextended. The load 302 supplies a component of force that isperpendicular to both the lateral dimension 124 and longitudinaldimension 122 of FIG. 1. The load 302 is distributed throughout thetruss-like configuration 304, as forces are generated through the pins114 and members 106 of the structure 100.

As the height H of the truss-like configuration 304 increases, whichresults from some retraction and a corresponding decrease in the lengthL in the longitudinal dimension 122, the load carrying capacityincreases. As the length L of the truss-like configuration 304increases, which results from some extension and a correspondingdecrease in the height H, the load carrying capacity decreases. As Hdivided by L approaches zero (i.e., maximum extension approachedresulting in a flat structure), there is no structural advantageotherwise provided by the truss-like configuration 304.

FIGS. 4 and 5 show another support structure embodiment 400 thatprovides a maximum extension limitation to promote the benefit from thetruss-like configuration and to further absorb a compression load. Thecompression loading increases the moment of inertia of the structure 400to provide a T-beam type of structure and load dispersion. Theextendable support structure 400 includes adjacent lazy tongs 402 and404 that are formed by a series of members 406 that are jointedtogether. Lazy tong 402 includes members 406 forming a row 418 that arepivotally connected to members 406 that form a row 416. The adjacentlazy tong 404 is formed of members 406 forming a row 420 that arepivotally connected to members 406 that form the row 416. Thus, the row416 forms a portion of the two adjacent lazy tongs 402 and 404.

Similar to FIG. 1, two lazy tongs 402, 404 are shown in FIG. 4 forillustrative purposes only, but one skilled in the art will recognizethat any number of lazy tongs may be included in the support structure400. The lateral dimension 424 of the extendable support structure 400is defined by the number of members 406 that are adjacent in the lateraldirection 422, where the number of members 406 define the total numberof lazy tongs that are present. The lazy tongs 402, 404 are extensible,and therefore, the extendable support structure 400 has a longitudinaldimension 422 that is variable depending upon whether the structure 400is fully retracted or extended to some degree. As shown, the structure400 is fully extended to provide a truss-like configuration andcompression loading discussed in more detail with reference to FIG. 6.

Each member 406 has a first end 408, a central portion 410, and acurvature 412 that causes each member 406 to be non-linear andasymmetrical. The members 406 of this embodiment 400 have holes 415 thatallow pins 414 to pass through. The pins 414 pass through the holes 415of the members 406 for each row 416, 418, and 420. Therefore, theadjacent lazy tongs 402 and 404 cooperate to extend and retract togetheras a unit. When extending the structure 400, the curvature 412 of onemember 406 will eventually contact the next member 406 of the same row,which is most evident in FIG. 5. The contact of the curvature 412 to themember 406 prevents further extension. One skilled in the art willrecognize that symmetrical non-linear members having curvatures on bothsides of the central portion 410 may also be used.

FIG. 6 shows a diagram 600 of the distribution of force relative to thetruss-like configuration 604 of the embodiment 400 when partiallyextended. The load 602 supplies a component of force that isperpendicular to both the lateral dimension 424 and longitudinaldimension 422 of FIG. 4. The load 602 is distributed throughout thetruss-like configuration 604, as forces are generated through the pins414 and members 406 holding the structure 400 together.

Again, as the height H of the truss-like configuration 604 increases,which results from some retraction and a corresponding decrease in thelength L in the longitudinal dimension 422, the load carrying capacityincreases. As the length L of the truss-like configuration 604increases, which results from some extension and a correspondingdecrease in the height H, the load carrying capacity decreases. Becausethe maximum extension occurs prior to the structure 400 becoming flat,the truss-like configuration 604 is preserved, and the resultingstructural advantage is maintained regardless of whether the curvature412 is present on the side where the load is applied or on the oppositeside.

When the load is applied to the same side of the structure 400 as thecurvatures 412, a compression loading 606 occurs at maximum extension ofthe structure 400. The compression loading 606 results in a decrease ofthe moment force about some of the pins 414 that hold the structure 400together. As discussed above, the structure 400 provides an increasedmoment of inertia and provides a T-beam type of structure when fullyextended due to the contact of the curvature 412 resulting in thecompression loading 606.

FIGS. 7 and 8 show another support structure embodiment 700 thatprovides a maximum extension limitation to promote the benefit from thetruss-like configuration and to further absorb a compression load and atension load. The compression and tension loading further increase themoment of inertia of the structure 700 thereby forming an I-beam type ofstructure and load dispersion. The extendable support structure 700includes adjacent lazy tongs 702 and 704 that are formed by a series ofmembers 706 that are jointed together. Lazy tong 702 includes members706 forming a row 718 that are pivotally connected to members 706 thatform a row 716. The adjacent lazy tong 704 is formed of members 706forming a row 720 that are pivotally connected to members 706 that formthe row 716. Thus, the row 716 forms a portion of the two adjacent lazytongs 702 and 704.

Similar to FIGS. 1 and 4, two lazy tongs 702, 704 are shown in FIG. 7for illustrative purposes only, and one skilled in the art willrecognize that any number of lazy tongs may be included in the supportstructure 700. The lateral dimension 724 of the extendable supportstructure 700 is defined by the number of members 706 that are adjacentin the lateral direction 722, where the number of members 706 define thetotal number of lazy tongs that are present. The lazy tongs 702, 704 areextensible, and therefore, the extendable support structure 700 has alongitudinal dimension 722 that is variable depending upon whether thestructure 700 is fully retracted or extended to some degree. As shown,the structure 700 is fully extended to provide a truss-likeconfiguration and both compression and tension loading discussed in moredetail with reference to FIG. 9.

Each member 706 has a central portion 710, a first portion 708 angledrelative to the central portion 710, and a second portion 712 alsoangled with respect to central portion 710. First and second portions708, 712 form curvatures that cause each member 706 to be non-linear.The members 706 of this embodiment 700 have holes 715 that allow pins714 to pass through. The pins 714 pass through the holes 715 of themembers 706 for each row 716, 718, and 720. Therefore, the adjacent lazytongs 702 and 704 cooperate to extend and retract together as a unit.

When extending the structure 700, catches 730 located on or near the endportions 708, 712 of one member 706 will eventually be received bynotches 732 located on the next members 706 of the same row at somepoint between the center and the endpoints of the next members 706. Thisis most evident in FIG. 8, where the notches are shown in the centralportion 710 only as an example. One skilled in the art will appreciatethat to maximize the compression and tension loading, it is desirable toextend the mating point of the notch with the catch as far as possiblefrom the center of the members 706 in the direction perpendicular to thelateral and longitudinal dimensions 724, 722 of the structure 700. Themating of the catches 730 to the notches 732, such as at points 726 and728, prevents further extension of the structure 700.

FIG. 9 shows a diagram 900 of the distribution of force relative to thetruss-like configuration 904 of the embodiment 900 when at leastpartially extended. The load 902 supplies a component of force that isperpendicular to both the lateral dimension 724 and longitudinaldimension 722 of FIG. 7. The load 902 is distributed throughout thetruss-like configuration 904, as forces are generated through the pins714 and members 706 of the structure 700.

Again, as the height H of the truss-like configuration 904 increases,which results from some retraction and a corresponding decrease in thelength L in the longitudinal dimension 722, the load carrying capacityincreases. As the length L of the truss-like configuration 904increases, which results from some extension and a correspondingdecrease in the height H, the load carrying capacity decreases. Becausethe maximum extension occurs prior to the structure 700 becoming flat,the truss-like configuration 904 is preserved, and the resultingstructural advantage is maintained.

Additionally, compression loading 906 and tension loading 908 occurs atmaximum extension of the structure 700. The compression loading 906 andtension loading 908 result in a decrease of the force through the pins714 that hold the structure 700 together. The structure 700 acts as anI-beam type of structure when fully extended due to the contact of thecatches 730 being received in the notches 732 resulting in thecompression loading 906 and tension loading 908. One skilled in the artwill recognize that non-symmetrical members 706 having only one portion708 or 712 angled with respect to the central portion 710 may also beused, and the one portion 708 or 712 can be positioned on the same sideas the load to provide compression loading 906 or positioned on theopposite side as the load to provide tension loading 908.

FIG. 10 shows the extendable support structure embodiment 700′ in itsfully retracted state. As can be seen by comparison of the retractedembodiment 700′ to the extended embodiment 700 of FIG. 7, thelongitudinal dimension of the embodiment 700′ is much shorter. It willbe apparent to one skilled in the art that the other various embodimentsdescribed herein also have a retracted state as shown in FIG. 10 for theembodiment 700′.

FIG. 11 shows the extendable support structure 700 partially explodedwhile in its extended state. Each member 706 has holes 715 that slideonto a pin 714 that extends across the lateral dimension 724 when theextendable support structure 700 is being assembled. The members 706 ofthis embodiment as well as the members of the other embodimentsdescribed herein may be made from various materials such as casted ormachined metals, from carbon composites, or from plastics such as byinjection molding. The pins 714 may be made from various materials suchas metal or carbon composites. The members may be solid except for theholes 715 or may have voids 734 as best shown in FIG. 8.

FIG. 12 shows an example of a member 1206 of one embodiment that usesintegral pin attachments rather than pins spanning the lateraldimension. The integral pin attachments are formed by integral pins 1214that extend from one side of the member 1206 and receptacles 1215 thatare positioned on the opposite side. The integral pin 1214 of one memberis disposed in a receptacle 1215 of an adjacent member 1206. Theintegral pin attachments allow the adjacent lazy tongs of the extendablesupport structure to extend and retract in the same manner as theembodiments using pins passing through holes in the members.

FIG. 13 shows two extendable support structures side by side where onestructure 1302 is fully retracted and another structure 1304 is fullyextended. The ratio of extension can be altered based upon the length ofthe individual members that make up the lazy tongs of the structures1302, 1304. The structures 1302, 1304 show examples having many moreadjacent lazy tongs than the two adjacent lazy tongs of FIGS. 1, 4, and7. Thus, as can be seen the lateral dimension of the extendable supportstructure can be set as needed for a particular application based uponthe number of adjacent lazy tongs that are included.

FIG. 14 shows one application for an embodiment of an extendable supportstructure. A vehicle 1400 such as a truck has a tailgate 1402 (moreclearly shown in FIGS. 15-17). An extendable support structure 1404 ispivotally attached to the tailgate at one end, typically the top end ofthe tailgate 1402. When the extendable support structure 1404 is in afully retracted state as shown in FIG. 14, the tailgate 1402 can beclosed.

When the extendable support structure 1404 is to be used, the tailgatemay be opened and the structure 1404 pivoted away from the tailgate 1402as shown in FIG. 15. Then, the extendable support structure 1404 can beextended by the user pulling on its free end away from the truck 1400until the structure 1404 has reached a suitable extended state 1404′, asshown in FIG. 16. The free end of the structure 1404 can be positionedon the ground or other surface, and then the structure 1404′ can be usedas a loading ramp or bridge to and from the bed of the truck 1400.Afterwards, the structure 1404′ can be stored by pushing the free endback toward the truck to retract the structure 1404′, pivoting theretracted structure 1404 back toward the tailgate 1402, and then closingthe tailgate 1402.

As shown in FIG. 17, the extended structure 1404′ may be provided withlegs 1406 so that the structure 1404′ acts as a table when extended. Oneskilled in the art will recognize that there are many uses for theextendable support structure embodiments discussed herein and that theexamples shown in FIGS. 14-17 are for illustrative purposes only. Someadditional uses include but are not limited to a safety mat for changinga tire on a soft shoulder of a roadway, evacuation ramps for aircraft,safety gates, awnings, and temporary barricades or ceilings.

FIG. 27 shows another application of an extendable support structure inrelation to a truck 1400. The truck 1400 has a truck bed 1410. Anextendable support structure 1412 shown in its extended state can beplaced atop the truck bed 1410 to form an extendable truck bed cover.The truck bed cover may provide several advantages, such as reducing theaerodynamic drag presented by a truck bed 1410 that is not covered. Whenobjects are to be placed in the truck bed 1410, the extendable supportstructure 1412 may be retracted to some degree to expose the truck bed1410 and then extended to cover the truck bed 1410 and objects that itcontains. Thus, the extendable truck bed cover structure 1412 canprovide protection and/or security for the objects within the truck bed1410. Additionally, the structure 1412 may provide a surface upon whichadditional objects may be placed and secured, thus effectivelyincreasing the surface area of the truck bed 1410.

FIG. 18 illustrates an additional application of an extendable supportstructure 1800. The structure 1800 is suitable for various uses,including a bridge, scaffold, or swing stage. The support structure 1800provides an extendable floor support structure 1802. The floor structure1802 includes adjacent lazy tongs having members of one particular size.The floor structure 1802 is bounded by extendable support structures1804 that includes adjacent lazy tongs having members of a sizedifferent than the size of the members of floor structure 1802. Thedifferent size members are established by proportioning the hole centersin the members of the structure 1804 to mate with at least some of thepins passing through the lateral dimension of the floor structure 1802.

The example in FIG. 18 includes an extendable rail support structure1806 suspended above the floor structure 1802 by posts 1808. When anindividual is standing on or walking across the support structure 1800,the rails 1806 provide stability and act as a barrier. When the supportstructure 1800 can be retracted, all of the individual extendablesupport structures retract to establish the retracted support structure1800′ of FIG. 19. This structure 1800′ includes a retracted floorstructure 1802′, retracted boundary structure 1804′, and retracted railstructure 1806′.

FIG. 20 shows another example of an application for the extendablesupport structure embodiments. In this example, the extendable supportstructure forms four walls 2002 that are connected to produce anexpandable room 2000. Because all four walls of the room are extendable,the corners 2004 may be fixed once the room has been expanded so thatforce against a particular wall 2002 toward the center of the room doesnot cause the adjacent walls 2002 to retract. One skilled in the artwill recognize that one or more walls may be an extendable supportstructure rather than all four. FIG. 21 shows the retracted room 2000′with retracted walls 2002′.

FIG. 22 shows an embodiment of an extendable support structure 2200where one row of lazy tong members are offset from an adjacent row oflazy tong members. The offset is produced by aligning an end hole ofmembers of one row with the central hole of members of an adjacent row.As shown, members 2206 of rows 2218 and 2216 (forming lazy tong 2202)are not offset so that a lower end hole 2208, central hole 2210, andupper end hole 2212 for members of row 2218 are aligned with a lower endhole, central hole, and upper end hole for members of row 2216. However,members 2206 of row 2220 and 2216 (forming lazy tong 2204) are offset byaligning the upper end hole of members of row 2216 with the central holeof members of row 2220, and aligning the central end hole of members ofrow 2216 with the lower hole of members of row 2220.

As can be seen, due to the offset the upper end hole 2214 of members ofrow 2220 is not aligned with a hole of row 2216 and the hole 2214 isavailable for alignment with other members. Thus, the offset allowsvarious structural forms to be produced such as inclinations orvariations in the lateral dimension. Additionally, the extendablesupport structure may have a shape such as a tube that extends andretracts in length by attaching additional lazy tongs to the holes thatare not aligned with holes of an adjacent member. For example, a row ofmembers may be placed over another row such that the offset row isadjacent to both of the stacked rows of members which is repeated untila tube is completed. The offset and any resulting shape does not affectthe extension and retraction capabilities, and the retracted structure2200′ having offset members and retracted rows 2216′, 2218′, and 2220′is shown in FIG. 23.

FIGS. 24 and 25 show an embodiment of an extendable support structure2400, and corresponding retracted structure 2400′, that establishes anarc over the longitudinal dimension when extended to some degree. Theradius of the arc increases as the structure 2400 is expanded further,and the arc prevents the structure 2400 from bowing when a load isapplied. The load bearing of the extendable structure 2400 isconsiderably increased by fixing the ends of the arc when it isextended, such as when being used as a bridge or a roof structure. Thesupport structure embodiment 2400 includes members having center holesthat are not equidistant from the end holes to thereby produce the arc.One skilled in the art will recognize that using members having centerholes that are offset so as to be non-equidistant from the end holesallows various shapes to be provided upon extension of the supportstructure, such as a single arc or other patterns like a sinusoid.

For example, one member may be used throughout the arc with a centerhole offset so as not to be equidistant from the end holes. FIG. 26shows a plane view of a section of the arc that illustrates the use of acommon member 2406 throughout the arc. Each member has a center hole2408 located a distance A from one end hole 2410 and a distance B fromthe other end hole 2412, where A is less than B. As can be seen, themembers 2406 are placed so that the lesser dimension A is on the side ofthe structure intended to be the inside of the arc. Although FIG. 26shows one common member 2406 and also shows dimension A of each memberon the inner side of the arc, one skilled in the art will also recognizethat different members may be intermixed with member 2406 in thestructure, such as where the distances of the center hole from the endholes are not A and B for the different members.

Although the present invention has been described in connection withvarious exemplary embodiments, those of ordinary skill in the art willunderstand that many modifications can be made thereto within the scopeof the claims that follow. Accordingly, it is not intended that thescope of the invention in any way be limited by the above description,but instead be determined entirely by reference to the claims thatfollow.

1-16. (canceled)
 17. An extendable support structure, comprising atleast one lazy tong providing a lateral dimension and comprisingnon-linear members, wherein the at least one lazy tong extends toprovide a variable longitudinal dimension, and wherein a curvature ispresent on the non-linear members that limits the longitudinal extensionto a maximum longitudinal dimension by abutting another member of the atleast one lazy tong when the at least one lazy tong is extended.
 18. Theextendable support structure of claim 17, further comprising adjacentlazy tongs disposed adjacently to the at least one lazy tong to providethe lateral dimension, and wherein the adjacent lazy tongs and at leastone lazy tong are fixed together laterally at at least one point. 19.The extendable support structure of claim 17, wherein a curvature ispresent on both ends of each non-linear member of the at least one lazytong.
 20. The extendable support structure of claim 18, whereinnon-linear members of the adjacent lazy tongs provide an integral pinand a receptacle and wherein the adjacent lazy tongs are connected by anintegral pin of one non-linear member of one lazy tong being disposedwithin a receptacle of one non-linear member of an adjacent lazy tong.21. The extendable support structure of claim 18, wherein non-linearmembers of the adjacent lazy tongs are connected by pins extendingthrough the non-linear members in the lateral dimension. 22-29.(canceled)